Transducer construction



Aug. 2, 1960 w. T. HARRls TRANsDucER coNsTRUc'rxoN Filed May ll, 1956 FIG.

R5 5 mw WM w l A TYM 0 w 8% W mvf FIG.V 3.

32 ff/Pff/rf United States Patent TRANSDUCER CONSTRUCTION Wilbur T. Harris, Southbury, C'onn., assignor to The Harris Transducer (l'orporation,v Woodbnry, Conn'., a corporation of Connecticut Filed May '11, 1956, ser. Na. 584,384 6 claim's. (ci. 810-26) v fluid medium.

- It is a further object to provide an improved transducer construction employing liquid cooling without impairing efliciency of operation.

It is also an object to provide an improved liquid-immersion transducer construction in which inadvertent or careless operation in air will not necessan'ly ruin the transducer.

It is a specific object to meet the above objects with a construction which may be unit-handling an'd which may be directly adaptable to a tank, or other vessel, within which a liquid is to be excited.

Other objects and various other features of novelty and invention will be pointed out or will occur to those skilled in the` vart from a reading of the following specification in conjunction with the accompanying drawings. In said drawings,`which show, for illustrative purposes only, preferred forms of the invention,

Fig. 1 is a longtudinal sectional view through a transducer assembly of my invention;

Fig. 2 is a partly broken-away fragmentary perspective view of the transducer of Fig. 1, the principal sectional cut of Fig. 2 being in the plane of Fig. 1; and

Fig. 3 is a fragmentary view similar to Fig. 1 and showing a modification.

Briefly stated, my invention contemplates a completely self-contained transducer assembly incorporating liquid filling, primarily for cooling and electrical-insulation purposes, and yet embodying means whereby the external response of the transducer is not thereby impaired. The invention is shown in application to a transducer comprising head and tail-weight members bonded `to longitudinal ends of plural electro-mechanical force elements, all contained within a housing, the interior of the housing being flooded with the liquid filling; eflicient output is achieved by directly exposing the driver externally of the assembly, so as to permit *direct coupling to' a liquid medium to be excited. Further efliciency results from decoupling the liquid filling from one or both of the head and tail weights, as by applying a pressure-release layer to the axially inner wall of one of the head and tail weights.

Referring to the drawings, my invention shown in ap- 'plication to a magnetostrictive transducer element contained within a cylindrical housing or can 11. The housing 11 includes a mounting flange 12 extending peripherally thereof and at essentally a single central location to permit adaptation of the transducer assembly to the wall 131of av tank or other vessel, containing fluid 'to be excited V z,947,888 Patented Aug. '2,' '1960 .'ice

2 by the transducer. A gasket 14 seals the transducer assembly in the tank wall 13 so that operation may proceed below the liquid level within the tank 13. For the ar'r'angement shown in the drawings, the liquid within the tank 13 at the end 15 exposed outside the vessel 13, while the endV facing into the vessel 13 may be open. The transducer proper is shown to include a head-weight, Vdiaphragm, or piston element 16 directly eXposed to the liquid to be excited and including a reduced cylindrical portion 17 longitudinally overlapping the open end of the housing 11 and preferably in close radia'l-clearance relation therewith. A longitudinally yieldable seal member, such as a ring 18 of rubber, neoprene, or the like, connects the head 16 to the open end of the housing 11 and yet resiliently yields to the driving displacements of the head 16; a circumferential groove 18' in the reduced cylindrical portion of'head 16 receives and locates ring 18 and holds the same in circurnferentially continuous radially stressed sealing engagement with the a'djacent part of the inner wall of housing 11.

The inner end 19 of ythe head-weight 16 is shown recessed at 20 to accommodate the head ends of various parts of the transducer element 10. In the form shown, the element 10 is of the general variety disclosed in said copending application and comprises a plurality of elongated legs 21-22 of magnetostrictive ,material joined at their respective longitudinal ends by magnetic fluX-conduoting means 23-24. The elements 21-22-23-24 may all be formed as a unit, but in the arrangement shown, each of the legs 21-22 is independent and comprises a consolidated stack of like laminations of magnetostrictive lstrip material; the view of Fig. 1 will be understood to dis- Winding means 25 is developed along'exposed lengths of the flux path defined by elements 21-23-22-24, and the arrows traversing these elements suggest polarized flux in this path. The sealed lead-in connection 26 may be made to the externally exposed part of the housing, 11 (i.e. outside the tank wall 13).

For greater efliciency, I provide loading for the tail of my transducer element and have shown a tail-Weight 27 which may be of cylindrical configuration having close radial-clearance relation with the housing 11 and recessed to receive the tail end of the transducer element 10. For applications in whichbi-directional radiation is desired, the back end of the tail-weight 27 may be directly connected to the back wall 15 of Vthe housing 1-1 (as shown inV Fig. 3, where these parts are bonded), but in the form shown in Figs. 1 and 2, unidirectional radiation is desired, and I therefore employ a layer of pressure-release material, such as the cork layer 29, -to connect the tail-weight 27 to the back wall 15, as by bonding' these parts. The back wall 15 may thus serve to centrally position the back end of the transducer element 10.

In accordance with the invention, I provide a liquid filling to flood the interior 30' of the housing 11. The

liquid may be transformer oil or a like dielectric liquid' for the purpose of dissipating heat generated within the to provide improved electrical insulation within the transducer. Furthermore, by thus immersing internal active parts of the transducer, I provide a measure of protection against permanent damage to the unit, should the assembly be inadvertently or carelessly excited in air.

In order further to enhance the efficiencyrof operation, I provide. pressure-release vmeans for decoupling the head and tail members 16-27 from the liquid filling. For certain applications, it may sufiice to provide a single Vpressure-release layer 31 (as of Cork) bonded to the tail face of the head-weight 16; thus, the exposed rear face 24' of themagnetic coupler 24 may be in essentially the same radial plane asV the exposed rear face 19 of the head-weight 16, so that the single layer 31 of pressure-release material may be applied over the full cross-sectional area of the housing 11, except for that displaced by the legs 21-22. In the form shown, I' indicate my Preference for a second decoupling pressure-releaseV 'layer 32 similarly applied to the head end 27' of the tail-Weight 2.7.

In operation, maximum coupling is achieved to the liquied contained'within the vessel 13 because the active i radiating member is directly exposed to the response medium; in Fig. 1, the head 16 is the radiating member, while in Fig. 3, both head 16 and tail 27-15 are the radiating members. Efficiency is promoted by fiooding the interior with dielectric heat-conducting liquid filling and by decoupling internal transducer end parts from this liquid filling.

It will be appreciated that I have described a highly efiicient transducer construction, particularly applicable to industrial use. The transducer assembly is selfcontained and readily mountable in the tank within which it is to be employed, Without requiring substantial servicing with liquid filling. The employment of liquid filling in no Way impairs, but on the other hand enhances, efficiency of operation of the device and additionally provides a means of protection against abuse or careless use.

While I have described the invention in detail for the preferred forms shown, it will be understood that modifications may be made within the scope of the invention as defined in the claims which follow.

I claim:

l. In a transducer of the Character indicated, an elongated cylindrical housing closed at one end and open at the other, a head-weight having a cylindrical portion longitudinally overlapping the open end of said housing with relatively close radial clearance, a yieldable seal member closing said clearance, said head-weight being recessed at the end facing the interior of said housing,

an elongated transducer element comprising two spaced elongated 'magnetostrictive legs and magnetic fluxconducting means bonded'to and joining the respective ends of opposite side walls of said legs to each other, one end of said legs and of one of magnetic fiuxconducting means being received in said recess, a tailweight recessed to accommodate the other ends of said legs and of the magnetic fiux-conducting means associated therewith, the interior exopsed face of said headweight and of the magnetic fluX-conducting means at the head end being in substantially the same radial plane, a layer of pressure-release material applied to said face and to the magnetic tlux-conducting means at said head end, and a liquid fiooding the interior of said housing.`

2. In a transducer of the character indicated, an elongated cylindrical housing closed at one endV and open at the other, a head-Weight having a cylindrical portion longitudinally overlapping the open end of said housing with -relatively close radial clearance, a yieldable seal member closing said clearance, said head-weight being recessed at the end Vfacing the interior of said housing, an elongated transducer element comprising two spaced elongated. magnetostrictive legs and. magnetic fluxconducting means bonded'to-and joiningthe respective ends of opposite side walls of said legs to each other,

and said magnetic tlux-conducting means at said head' end, and a liquid flooding the interior of said housing.

3.' In a transducer of the Character indicated, an elongated cylindrical housing closed at oneV end and open at the other, a head-weight having a cylindrical portion longitudinally overlappingrthe open end of said housing with relatively close radial clearance, a yieldable seal member closing said clearance, said head-weight being recessed at the end facing the interior of said housing, an elongated transducer element comprising two spaced elongated magnetostrictive legs and magnetic fluX-conducting means bonded to and joining the respective ends of opposite side walls of said legs to each other, one end of said legs and of one of said magnetic fluxconducting means being received in said recess, a tailweight recessed to accommodate the other ends of said legs and of the magnetic fiux-conducting means associated therewith, a layer of pressure-release material applied to the axially inner surfaces of said tail-weight and Vthe magnetic fiux-conducting means at said tail end, and a liquid fiooding the interior of said housing.

4. In a transducer of the Character indicated, an elong'ated cylindrical housing closed at oneend and open at the other, a head-weight having a cylindrical portion longitudinally ovcrlapping the open end of said housing with relatively close radial clearance, a yieldableseal member closing said clearance, said head-weight being recessed at the end facing the interior of said housing, an elongated transducer element comprising two spaced elongated magnetostrietive legs and magnetic fiux-conducting means bonded to and joining the respective ends of opposite side walls of said legs to each other, one end of said legs and of one of said magnetic fiuX-conducting means being received in said recess, a tail-weight recessed to accommodate the other ends of said legs and of the magnetic flux-conducting means associated therewith, a layer of pressure-release material applied to the axially inner surfaces of one of said head-Weight and said tail-weight and of the magnetic fiux-conducting means at the corresponding end of said transducer element, and a liquid fiooding the interior of saidhousing.

5. In a transducer of the character indicated, an elongated magnetostrictive element comprising two spaced rectangularly prismatic legs in face-to-face relation, magnetic fiux-conducting means bonded to and joining the respective ends of adjacent faces of said legs, thereby defming a single flux-conducting path through said legs, said path being polarized to circulate fluX in one leg and out the other leg, winding means including turns linked to said legs, a cylindrical head-weight member of greater cross-sectional area than said element and bonded to said element at one end thereof, a cylindrical tail-weight member of greater cross-sectional area than said element and bonded to the other end of said element, a cylindrical housing closed at one end and open at the other and fully containing said element and said tailweight member With a portion of said head-weight member in axially-overlapping close clearance relation with the bore of said housing near the open end thereof, an axially yieldable circumferentially continuous seal between said head-weight member and said housing at the region of overlap, and a filling of dielcctric liquid ilooding said element within said housing, said head-weight member and said tail-weight member being each recessed at their opposed faces, said recesses axially receiving therespective ends of said element including portions of said fiuX-conducting means at each end respectively.

6; In .the transducer of claim 5, a layer of pressure-`` References Cited in the file of this patent UNITED STATES PATENTS 2,044,8-07 Noyes June 23, 1936 2,076,330 Wood et al. Apr. 6, 1937 2,116,522 Kunze May 10, 1938 6 Bundy Dec. 25, 1945 Mason July 4, 1950 Carwile Sept. 8, 1953 Brown Jan. 29, 1957 Harris July 8, 1958 FOREIGN PATENTS Germany Jan. 26, 1953 Germany Nov. 12, 1953 Germany Nov. 23, `1953 

